Continuously variable transmission cooling

ABSTRACT

A continuously variable transmission (CVT), wherein the CVT includes a housing having an inner cover and an outer cover connected to the inner cover to provide the housing having an interior chamber defined therein. The CVT additionally comprises a clutch assembly disposed within the housing interior chamber, wherein the clutch assembly comprises a clutch post that is connectable to an output shaft of a vehicle prime mover, a movable sheave movably mounted on the clutch post, and a stationary sheave fixedly mounted on the clutch post opposite a front face of the movable sheave. The clutch assembly additionally comprises an intake fan fixedly mounted to the clutch post opposite a rear face of the movable sheave such that the intake fan is separate, independent and spaced apart from the movable sheave.

FIELD

The present teachings relate to continuously variable transmissions(CVTs), and more particularly to systems and method for cooling CVTs.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

Many of today's lightweight vehicles that are not designated for use onroadways, e.g., all-terrain vehicles (ATVs), utility terrain vehicles(UTVs), etc., implement a continuously variable transmission (CVT) totransfer and control the distribution of torque within the vehicledrivetrain. Due to the dust, water, mud, rocks, etc., commonlyencountered in off-road environments, such CVTs typically comprise ahousing or cover designed to protect the components, e.g., primaryclutch, secondary clutch, bushings, belts, etc., from the environment.However, such covers substantially enclose the components and trap heatgenerated during operation of the CVT such that the components do noteasily cool off causing degradation in the life of the components.Additionally, in higher horsepower vehicles, greater heat is generated,which will degrade the internal parts of the CVT faster. Known systemdesigns for cooling the internal components of CVTs have a fan locatedon the inside, or stationary, sheave of the primary clutch and/or theoutside, or stationary, sheave of the secondary clutch. However, suchlocations limit the size that the fan can be and typically require thatthe fan be integrally formed in the respective sheave.

SUMMARY

In various embodiments, the present disclosure provides a continuouslyvariable transmission (CVT), wherein the CVT includes a housing thatcomprises an inner cover and an outer cover. The inner and outer coversare connected to form the housing such that the housing has an interiorchamber. The CVT additionally includes a clutch assembly disposed withinthe housing interior chamber. In various embodiments, the clutchassembly comprises a clutch post that is connectable to an output shaftof a vehicle prime mover, a movable sheave movably mounted on the clutchpost, and a stationary sheave fixedly mounted on the clutch postopposite a front face of the movable sheave. The clutch assemblyadditionally comprises an intake fan fixedly mounted to the clutch postopposite a rear face of the movable sheave such that the intake fan isseparate, independent and spaced apart from the movable sheave.

While the present disclosure is primarily described with regard to anair induction cooled CVT for use in an off-road utility vehicle, itshould be understood that the features of the CVT disclosed herein canbe applied, within the scope of the disclosure, to other types ofvehicles such as most lightweight vehicles that are not designated foruse on roadways, e.g., maintenance vehicles, cargo vehicles, shuttlevehicles, golf carts, other all-terrain vehicles (ATVs), utility taskvehicles (UTVs), recreational off-highway vehicles (ROVs), side-by-sidevehicles (SSVs), worksite vehicles, buggies, motorcycles, watercrafts,snowmobiles, tactical vehicles, etc.

This summary is provided merely for purposes of summarizing variousexample embodiments of the present disclosure so as to provide a basicunderstanding of various aspects of the teachings herein. Variousembodiments, aspects, and advantages will become apparent from thefollowing detailed description taken in conjunction with theaccompanying drawings which illustrate, by way of example, theprinciples of the described embodiments. Accordingly, it should beunderstood that the description and specific examples set forth hereinare intended for purposes of illustration only and are not intended tolimit the scope of the present teachings.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present teachings in any way.

FIG. 1 is a side view of a utility vehicle including an air inductioncooled continuously variable transmission (CVT), in accordance withvarious embodiments of the present disclosure.

FIG. 2 is a schematic of a chassis, a prime mover and a drivetrain ofthe vehicle shown in FIG. 1, in accordance with various embodiments ofthe present disclosure.

FIG. 3 is an isometric exploded view of the CVT shown in FIG. 1 operablycoupled to an engine and gearbox of the vehicle shown in FIG. 1, inaccordance with various embodiments of the present disclosure.

FIG. 4 is a side view of a clutch assembly of the CVT shown in FIGS. 1and 3, in accordance with various embodiments of the present disclosure.

FIG. 5 is an isometric exploded view of the clutch assembly shown inFIG. 4, in accordance with various embodiments of the presentdisclosure.

FIG. 6 is an isometric exploded view of the CVT shown in FIG. 1 operablycoupled to an engine and gearbox of the vehicle shown in FIG. 1, andhaving an air flow control housing outer cover, in accordance withvarious embodiments of the present disclosure.

FIG. 7 is an isometric view of the CVT housing with the air flow controlhousing outer cover shown in FIG. 6, in accordance with variousembodiments of the present disclosure.

FIG. 8 is an isometric view of an interior side of an air flow controlhousing outer cover, in accordance with various other embodiments of thepresent disclosure.

FIG. 9 an isometric view of an interior side of the outer cover shown inFIGS. 6 and 7, in accordance with various embodiments of the presentdisclosure.

FIG. 10 is a view of an interior face of an inner cover of the housingshown in FIGS. 3 and 6 having an airfoil, in accordance with variousembodiments of the present disclosure.

FIG. 11 is a view of the interior face of the housing outer cover shownin FIG. 3 having an airfoil, in accordance with various embodiments ofthe present disclosure.

FIG. 12 is a view of the interior face of the housing outer cover shownin FIG. 8 having an airfoil, in accordance with various embodiments ofthe present disclosure.

FIG. 13 is a view of the interior face of the housing outer cover shownin FIGS. 6, 7 and 9 having an airfoil, in accordance with variousembodiments of the present disclosure.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of drawings.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is in no wayintended to limit the present teachings, application, or uses.Throughout this specification, like reference numerals will be used torefer to like elements. Additionally, the embodiments disclosed beloware not intended to be exhaustive or to limit the invention to theprecise forms disclosed in the following detailed description. Rather,the embodiments are chosen and described so that others skilled in theart can utilize their teachings. As well, it should be understood thatthe drawings are intended to illustrate and plainly disclose presentlyenvisioned embodiments to one of skill in the art, but are not intendedto be manufacturing level drawings or renditions of final products andmay include simplified conceptual views to facilitate understanding orexplanation. As well, the relative size and arrangement of thecomponents may differ from that shown and still operate within thespirit of the invention.

As used herein, the word “exemplary” or “illustrative” means “serving asan example, instance, or illustration.” Any implementation describedherein as “exemplary” or “illustrative” is not necessarily to beconstrued as preferred or advantageous over other implementations. Allof the implementations described below are exemplary implementationsprovided to enable persons skilled in the art to practice the disclosureand are not intended to limit the scope of the appended claims.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. The terminology used herein isfor the purpose of describing particular example embodiments only and isnot intended to be limiting. As used herein, the singular forms “a,”“an,” and “the” may be intended to include the plural forms as well,unless the context clearly indicates otherwise. The terms “comprises,”“comprising,” “including,” and “having,” are inclusive and thereforespecify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof. The method steps,processes, and operations described herein are not to be construed asnecessarily requiring their performance in the particular orderdiscussed or illustrated, unless specifically identified as an order ofperformance. It is also to be understood that additional or alternativesteps can be employed.

When an element, object, device, apparatus, component, region orsection, etc., is referred to as being “on,” “engaged to or with,”“connected to or with,” or “coupled to or with” another element, object,device, apparatus, component, region or section, etc., it can bedirectly on, engaged, connected or coupled to or with the other element,object, device, apparatus, component, region or section, etc., orintervening elements, objects, devices, apparatuses, components, regionsor sections, etc., can be present. In contrast, when an element, object,device, apparatus, component, region or section, etc., is referred to asbeing “directly on,” “directly engaged to,” “directly connected to,” or“directly coupled to” another element, object, device, apparatus,component, region or section, etc., there may be no interveningelements, objects, devices, apparatuses, components, regions orsections, etc., present. Other words used to describe the relationshipbetween elements, objects, devices, apparatuses, components, regions orsections, etc., should be interpreted in a like fashion (e.g., “between”versus “directly between,” “adjacent” versus “directly adjacent,” etc.).

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. For example, A and/or Bincludes A alone, or B alone, or both A and B.

Although the terms first, second, third, etc. can be used herein todescribe various elements, objects, devices, apparatuses, components,regions or sections, etc., these elements, objects, devices,apparatuses, components, regions or sections, etc., should not belimited by these terms. These terms may be used only to distinguish oneelement, object, device, apparatus, component, region or section, etc.,from another element, object, device, apparatus, component, region orsection, etc., and do not necessarily imply a sequence or order unlessclearly indicated by the context.

Moreover, it will be understood that various directions such as “upper”,“lower”, “bottom”, “top”, “left”, “right”, “first”, “second” and soforth are made only with respect to explanation in conjunction with thedrawings, and that components may be oriented differently, for instance,during transportation and manufacturing as well as operation. Becausemany varying and different embodiments may be made within the scope ofthe concept(s) herein taught, and because many modifications may be madein the embodiments described herein, it is to be understood that thedetails herein are to be interpreted as illustrative and non-limiting.

Referring to FIGS. 1, 2 and 3, in various embodiments, the presentdisclosure provides an off-road utility vehicle 10 that generallyincludes a chassis or frame 14, a pair of rear wheels 18 and a pair offront wheels 22 operationally connected to the chassis 14 and/or otherstructure of the vehicle 10, and a passenger compartment 26. The vehicle10 can be any four-wheel drive or two-wheel drive lightweight vehiclethat is not designated for use on roadways. For example, it isenvisioned that the vehicle 10 can be a maintenance vehicle, cargovehicle, shuttle vehicle, golf cart, other all-terrain vehicles (ATV),utility task vehicle (UTV), recreational off-highway vehicle (ROV),side-by-side vehicle (SSV), worksite vehicle, buggy, motorcycle,watercraft, snowmobile, tactical vehicle, etc. The passenger compartment26 generally includes a dash console 30, a steering wheel 34, afloorboard (not shown, but understood), and a passenger seatingstructure 38. The vehicle 10 additionally includes a prime mover 42mounted to the chassis 14, and a drivetrain 44 operationally connectedto at least one of the front and/or rear wheels 22 and/or 18 and theprime mover 42. The prime mover 42 is structured and operable togenerate torque (e.g., motive force, e.g., power) utilized to providemotive force for the vehicle 10 via the drivetrain 44. Although theprime mover 42 is primarily described herein as an internal combustionengine (ICE), it should be understood that the prime mover 42 can be anelectric motor, a hybrid combination of an ICE and an electric motor, orany other suitable motor or engine and remain within the scope of thepresent disclosure.

In various embodiments, the drivetrain 44 includes an air inductioncooled continuously variable transmission (CVT) 46 that is operablyconnected to the prime mover 42 to receive torque (e.g., motive force,e.g., power) from the prime mover 42, and operably connected to at leastone of the rear and front wheels 18 and 22 to deliver torque to at leastone of the rear and front wheels 18 and 22. In various embodiments, theCVT 46 can be operably connected to at least one of the rear wheel(s) 18and the front wheel(s) 22 via one or more rear and/or front wheel axles52 and/or 62 that are operably connected to the CVT 46. Additionally, invarious embodiments the CVT 46 can be operably connected to at least oneof the rear and front wheels 18 and 22 via a first gearbox 50. In suchembodiments, the first gearbox 50 is operably connected to the CVT 46and at least one rear and front wheel 18 and 22 is operably connected tothe first gearbox 50 via one or more rear and/or front wheel axles 52and/or 62 and/or a driveshaft 54. For simplicity, the CVT 46 will bedescribed herein as operably connected to at least one of the rear andfront wheels 18 and 22 via the first gearbox 50. The first gearbox 50can be a torque transfer device such as a transmission and/or adifferential and/or a transaxle, etc. For example, in variousimplementations, the first gearbox 50 can be a multi-speed gearbox and,in various instances, include a differential for distributing the torqueto one or more of the wheels 18 and/or 22.

In various embodiments, the CVT 46 is structured and operable to receivetorque (e.g., motive force, e.g., power) generated by the prime mover 42and controllably transfer the torque to the first gearbox 50.Particularly, when transferring the torque to the first gearbox 50, theCVT 46 is structured and operable to controllably vary the amount oftorque delivered to the gearbox 50. That is, the amount of torquedelivered can controllably be increased, decreased and/or not changedvia operation of the CVT 46. The first gearbox 50 is structured andoperable to transfer and distribute the torque to one or more of thewheels 18 and/or 22. For example, in various embodiments, the firstgearbox 50 can be operably connected to a rear axle 52 and structuredand operable to transfer and distribute the torque output by the CVT 46to at least one of the rear wheels 18. In various other embodiments, inaddition to transferring and distributing the torque to at least one ofthe rear wheels 18, the first gearbox 50 can include a power take off(PTO) such that the first gearbox 50 can also transfer and distributethe torque output by the CVT 46 to at least one of the front wheels 22.In such embodiments, the drivetrain 44 can include a driveshaft 54 and asecond gearbox (or differential) 58, wherein the driveshaft 54 isoperably connected at one end to the CVT 46 or the first gearbox 50 viathe PTO and operably connected at the opposing end to the second gearbox58. The second gearbox 58 is structured and operable to transfer anddistribute the torque output by the CVT 46 to one or more of the frontwheels 22 via a front axle 62.

Hence, in various embodiments, the drivetrain 44 can be configured toprovide a 4-wheel drive (4WD) vehicle or a 2-wheel drive (2WD) vehicle,and remain within the scope of the present disclosure. In variousembodiments in which the drivetrain 44 is configured to provide a 2WDvehicle, the vehicle 10 can be driven by the rear wheels 18 (e.g., arear wheel drive vehicle) or by the front wheels 22 (e.g., a front wheeldrive vehicle). In some embodiments in which the vehicle 10 can beconfigured as a 4WD vehicle, the vehicle 10 can be selectively operatedin two or more drive modes, such as a 2WD mode and a 4WD mode, throughactuation of a switch or other user input device that can be disposed onthe instrument panel 30, or elsewhere.

Additionally, although the prime mover 42 and CVT 46 are illustrated, byway of example, in the various figures to be at least partially disposedrearward of a longitudinal center of the vehicle 10, it is envisionedthat the prime mover 42 and CVT 46 can be disposed anywhere along alongitudinal axis of the vehicle 10 and remain within the scope of thepresent disclosure. For example, in various embodiments, the prime mover42 and/or the CVT 46 can be disposed forward of the longitudinal centerof the vehicle 10, e.g., forward of a forward most part of the seatingstructure 38. Furthermore, although the prime mover 42, the CVT 46, andthe first gearbox 50 are shown, by way of example, to be directlyconnected with each other, it should be understood that the drivetrain44 can include one or more driveshafts (such as driveshaft 54) thatoperably interconnect one or more of the prime mover 42, the CVT 46, thefirst gearbox 50 and/or the second gearbox 58 based on the respectivelocation of the prime mover 42 and CVT 46 along the vehicle longitudinalaxis, and the respective 2WD or 4WD configuration of the drivetrain 44.

As used herein, the word “forward” and the phrase “forward of” are usedto describe the direction from a named component or structure toward thefront of the vehicle 10. For example, the statement that the prime mover42 is mounted to the chassis 14 “forward of” the longitudinal centermeans the prime mover 42 is mounted to the chassis 14 within an areathat extends from the longitudinal center of the chassis 14 to the frontof the chassis 14 at the front of the vehicle 10 (e.g., adjacent thefront wheels 22 positioned at the front of the vehicle 10 in theillustrated embodiment). Similarly, as used herein, the word “rearward”and the phrase “rearward of” are used to describe the direction from anamed component or structure toward the rear of the vehicle 10. Forexample, the statement that the prime mover 42 is mounted to the chassis14 “rearward of” the longitudinal center means the prime mover 42 ismounted to the chassis 14 within an area that extends from thelongitudinal center of the chassis 14 to the rear of the chassis 14 atthe rear of the vehicle 10 (e.g., adjacent the rear wheels 18 positionedat the rear of the vehicle 10 in the illustrated embodiment).

Referring now to FIG. 3, the CVT 46 generally includes a primary clutchassembly 70, a secondary clutch assembly 74, a drive belt 78 thatoperably connects the primary clutch assembly 70 to the secondary clutchassembly 74 and housing 80. The housing 80 is structured to enclose theprimary clutch assembly 70, secondary clutch assembly 74, and drive belt78 within an interior chamber 82 of the housing 80. The housing 80protects the primary clutch assembly 70, the secondary clutch assembly74, the drive belt 78 from water, mud, dirt and other debris present inthe ambient (exterior) environment. In various embodiments, the housing80 comprises an inner cover 80A and an outer cover 80B that isconnectable to the inner first cover 80A to define the interior chamber82. The inner first cover 80A includes a torque/power input opening 84that is sized and shaped to allow an output shaft 86 of the prime mover42 to extend therethrough. The inner first cover 80A additionallyincludes a torque/power output opening 90 that is sized and shaped toallow the secondary clutch assembly 74 to be operably connected, (e.g.,via the first gearbox 50) to at least one of the rear and/or front axles52 and/or 62 such that torque/power output by the secondary clutchassembly 74 is delivered to at least one of the rear and/or front wheels18 and/or 22. For example, in various instances, the torque/power outputopening 90 can be sized and shaped to allow an input shaft 94 of thefirst gearbox 50 to extend therethrough.

The primary clutch assembly 70 is operably connectable to the primemover output shaft 86 such that torque/power generated by the primemover 42 will be delivered to the primary clutch assembly 42,whereafter, via the drive belt 78, the primary clutch assembly 70 willtransfer torque/power to the secondary clutch assembly 74. Thereafter,the torque/power received at the secondary clutch assembly 74 will bedelivered to at least one of the rear and/or front axles 52 and/or 62.For example, in various embodiments wherein the drivetrain 44 includesthe first gearbox 50, the secondary clutch assembly 74 can transfer thereceived torque/power to the first gearbox 50, via the first gearboxinput shaft 94, and consequently to the rear and/or front axles 52and/or 62.

In various embodiments, the primary clutch assembly 70 is structured andoperable to deliver a continuously variable torque to the secondaryclutch assembly 74. That is, the primary clutch assembly 70 isstructured and operable to continuously variably increase, maintainunchanged, and decrease the torque/power received from the prime moveroutput shaft 86 when transferring the torque/power to the secondaryclutch assembly 74. Put another way, a torque/power transfer ratio ofthe torque/power received by the primary clutch assembly 70 from theprime mover 42 versus the torque/power delivered to the secondary clutchassembly 74 from the primary clutch assembly 70 can be continuouslyvaried via operation of the primary clutch assembly 70.

Referring now to FIGS. 3, 4 and 5, in various embodiments, one or bothof the primary and secondary clutch assemblies 70 and/or 74 can comprisethe following components that are structured and operable to function inthe manner described below. Particularly, in various embodiments, one orboth of the primary and secondary clutch assemblies 70 and/or 74 cancomprise an intake fan 98 as described below. However, for simplicityand clarity, by way of example, only the primary clutch assembly 70 willbe described to comprise the intake fan 98 and the operation andfunctionally of the intake fan 98 will be described, by way of example,only with regard to the primary clutch assembly 70. However, it will beeasily and readily understood by one skilled in the art that thedescription herein relating to the intake fan 98 with regard toembodiments of the primary clutch assembly 70 is merely an example, andsuch description is equally applicable with regard to embodiments of thesecondary clutch 74 and is wholly within the scope of the presentdisclosure.

In various embodiments, the primary clutch assembly 70 comprises aclutch post 102, a stationary (or static) sheave 106 that is fixedlymounted to the clutch post 102, and a movable (or dynamic) sheave 110that is movably mounted to the clutch post 102. The clutch post 102, andhence the primary clutch assembly 70, is fixedly connectable to theprime mover output shaft 86 via a clutch bolt 114 such that the primaryclutch assembly 70 will rotate in accordance with rotation of the outputshaft 86 and will thereby receive the torque/power generated by theprime mover 42. More particularly, the movable sheave 110 is structuredand operable to rotate with the output shaft/clutch post 86/102 andsimultaneously controllably move axially along the clutch post 102 inthe X⁺ and X⁻ directions. The stationary sheave 106 includes a beveledfront face 116. Similarly, the movable sheave 110 comprises a beveledfront face 118 that is disposed opposite (e.g., disposed face to face)the stationary sheave beveled front face 116. The movable sheave 110further includes a linear movement mechanism 122 that is structured andoperable to controllably move the movable sheave 110 axially along theclutch post 102 in the X+ and X⁻ directions. A V-shaped channel 126 isformed between the opposing beveled front faces 116 and 118 of thestationary and movable sheaves 106 and 110, and the drive belt 78 isdisposed within the V-shaped channel 126. Controlled axial movement ofthe movable sheave 110 in the X⁺ and X⁻ directions along the clutch post102, via the linear movement mechanism 122, varies a width of theV-shaped channel 126. The controlled varying of the channel 126 varies adiameter, or radial distance from the clutch post 102, at which thedrive belt 78 travels within the V-shaped channel 126, which in turnvarious the torque transfer ratio of the primary clutch assembly 70 tothe secondary clutch assembly 74. Therefore, the torque/power output bythe secondary clutch assembly 74 (e.g., the torque/power output by thesecondary clutch assembly 74 to the first gearbox 50) can becontrollably varied by the controlled linear movement of the movablesheave 110.

In various embodiments, the axial movement of the movable sheave 110along the clutch can be controlled by a vehicle controller and/or a CVTcontroller (not shown). Such a CVT controller can be a controller thatis communicatively connected to, or integrated as part of, a mainvehicle controller that is typically understood to be an embedded systemthat controls one or more of electrical systems and/or subsystems thevehicle 10. Generally, such a CVT controller can be any suitablehardware and/or software (e.g., software instructions stored on anon-transitory computer readable medium that can be read and performedby one or more processors) based controller that is structured andoperable to control operation of the CVT 46 as described herein. Forexample, it is envisioned that such a CVT controller can comprise one ormore, or be part of, application specific integrated circuit(s) (e.g.,ASIC(s)), combinational logic circuit(s); field programmable gatearray(s) (FPGA); processor(s) (shared, dedicated, or group) that executesoftware code; and/or other suitable hardware components that providethe CVT functionality described herein and remain within the scope ofthe present disclosure.

As described above, by way of example, in various embodiments, theprimary clutch assembly 70 includes the intake fan 98. Moreparticularly, in such embodiments, the intake fan 98 is fixedly mountedto the clutch post 102 opposite a back face 130 of the movable sheave110 (e.g., disposed face to face, e.g., disposed with movable sheaveback face 130 facing fan back face 134) such that the intake fan 98 isindependent, separate, distinct and spaced apart from the back face 130of the movable sheave 110. More specifically, the intake fan 98 is anindependent, separate, distinct component of the primary clutch assembly70 and is independent, separate and distinct from both the stationaryand movable sheaves 106 and 110. The intake fan 98 can be mounted to theclutch post 102 in any suitable manner. For example, in variousembodiments, the intake fan 98 can be compressed between a lock washer128, a retaining washer 132 and a head washer 136 as the clutch bolt 114is tightened to fixedly connect the intake fan 98 to the clutch post102. The retaining washer 132 and head washer 136 allows most orsubstantially all the compressive force to transfer through the lockwasher 128, head washer 134, and retaining washer 132 and not throughthe intake fan 98. In various instances, the retainer washer 132 isstructured to ensure that the intake fan 98 is centered on the clutchpost 102.

In various embodiments, a slack section 102A of the clutch post 102generally extends beyond the back face 130 of the movable sheave 110. Asdescribed above, during operation of the primary clutch assembly 70, themovable sheave 110 controllably moves, or transitions, (via operation ofthe linear movement mechanism 122) along the clutch post 102 in the X⁻and X⁺ directions to adjust the space between the beveled front faces116 and 118 to controllably adjust the torque/power transferred to thesecondary clutch assembly 74. Moreover, as the moveable sheave 110moves/transitions in the X⁻ and X⁺ directions along the clutch post 102,a length L of the slack section 102A will increase and decrease. Thelength L is defined to be the distance between the back face 130 of themovable sheave 110 and a back face 134 of the intake fan 98. Forexample, the length L of the slack section 102A will be a maximum lengthwhen the movable sheave 110 is moved/transitioned as far in the X⁻direction toward the stationary sheave 106 as the operational limits ofthe primary clutch assembly allow. Conversely, the length L of the slacksection 102A will be a minimum length when the movable sheave 110 ismoved/transitioned as far in the X⁺ direction away from the stationarysheave 106 as the operational limits of the primary clutch assemblyallow.

Still more particularly, the clutch post 102 is structured to have alength (not shown but understood) such that the length L of the slacksection 102A allows the moveable sheave 110 to move as far in the X⁺direction away from the stationary sheave 106 as the operational limitsof the primary clutch assembly allow without the back face 130 of themoveable sheave 110 contacting the back face 134 of the intake fan 98.In various embodiments, the slack section of the clutch post 102 can bebetween 1.0 inches and 2.50 inches. Furthermore, in various embodimentsthe minimum length of the clutch post slack length 102A (e.g., thelength of the slack length L when the movable sheave 110 ismoved/transitioned as far in the X⁺ direction away from the stationarysheave 106 as the operational limits of the primary clutch assemblyallow) can be between 0.05 and 0.50 inches. Hence, the length of clutchpost 102 and the length L of the clutch post slack section 102A are suchthat the primary clutch (e.g., the stationary and movable sheaves 106and 110) can operate (e.g., the movable sheave 110 can controllablymove/transition along the clutch post 102 the X⁻ and X⁺ directions)without the movable sheave 110 contacting the intake fan 98.Particularly, the length of clutch post 102 and the length L of theclutch post slack section 102A are such that the location andorientation of the intake fan 98 within the CVT housing 80 is generallyfixed and does not change. More particularly, the location andorientation of the intake fan 98 relative to an interior face 138 of thehousing outer cover 80B is generally fixed and does not change. Stillmore particularly, the length of clutch post 102 and the length L of theclutch post slack section 102A are such that an outer face 142 of theintake fan 98 is generally a fixed distance D from the interior face 138of the outer housing cover 80B.

The intake fan 98 comprises a plurality of fins 146 that define theouter face 142 of the intake fan 98. The size, shape and dimensions ofthe intake fan 98 can be any desired size, shape and dimensions suitablefor desirably cooling the respective CVT 46 when operated in therespective application and environment. Additionally, the size, shape,dimensions, number and configuration of the fins 146 can be any desiredsize, shape, dimensions, number and configuration suitable for desirablycooling the respective CVT 46 when operated in the respectiveapplication and environment.

In various embodiments, the housing outer cover 80B includes an airintake port 150 that fluidly connects the ambient air from an ambientenvironment external to the housing 80 with the interior chamber 82 ofthe housing 80. The air intake port 150 is located in the housing outercover 80B such that the intake port 150 is generally opposite (e.g.,disposed face to face) and aligned with a center of the intake fan 98and an inner radius of the fins 146, (e.g., the intake port 150 isgenerally opposite (e.g., disposed face to face) and aligned with a headof the clutch bolt 114). As described above, the length of clutch post102 and the length L of the clutch post slack section 102A are such thatthe outer face 142 of the intake fan 98 is the generally fixed distanceD from the interior face 138 of the outer housing cover 80B. Moreover,the distance D has a length such that the space between the intake fanouter face 142 and the outer housing cover interior face 138 defines alow pressure gap 148. The distance D will also be referred to herein asthe width of the low pressure gap 148. The width D of the low pressuregap 148 has a length such that when the intake fan 98 is rotated, viarotation of the clutch post 102 by the prime mover output shaft 86, anarea of low pressure is generated within a low pressure gap 148. Thearea of low pressure in turn generates a vacuum effect, or suction, atthe air intake port 150 and within the low pressure gap 148, wherebyambient air will be drawn into the housing interior chamber 82 at ornear the center of the intake fan outer face 142. The ambient air drawninto the center of the intake fan 98 is then forced radially outward bythe fins 146 into the interior chamber 82, thereby generating airflowwithin the interior chamber 82 that cools the primary and secondaryclutch assemblies 70 and 74 and the drive belt 78, as described below.In various embodiments, the width D of the low pressure gap 148 can bebetween approximately 0.010 and 0.30 inches, for example, betweenapproximately 0.10 inches to 0.20 inches, e.g., between approximately0.050 and 0.10.

As used herein, the term ‘vacuum effect’ will be understood to mean thesuction or drawing of air from a first area (e.g., the ambientenvironment) to a second area (e.g., the interior chamber 82 of thehousing 80) caused by creating a lower pressure within the second area(e.g., within the low pressure gap 148) than exists at the first area(e.g., the ambient environment). For example, due to the structure ofthe intake fan 98 and width D of the low pressure gap 148 (e.g.,location of the intake fan outer face 142 relative to the outer coverinterior face 138), rotation of the intake fan 98 creates a lower airpressure within the low pressure gap 148 than is present in the ambientenvironment external to the housing 80, thereby generating a vacuumeffect that will draw air from the ambient environment into the housinginterior chamber 82 via the air intake port 150.

The housing 80 additionally includes an air exhaust outlet 154 thatfluidly connects the interior chamber 82 with the ambient environment.It is envisioned that the exhaust outlet 154 can be formed within theinner cover 80A, within the outer cover 80B, or a combination thereofwhen the inner and outer covers 80A and 80B are connected. Accordingly,as described above, rotation of the intake fan 98 generates a vacuum, orsuction, at the air intake port 150 that draws cool ambient air into thehousing interior chamber 82. Subsequently, the rotation of the intakefan 98 (e.g., rotation of the fins 146) disperses the air radiallyoutward to the distal ends, or outer radius, of the fins 146.Thereafter, rotation of the intake fan 98, combined with rotation of theprimary and secondary clutch assemblies 70 and 74 and rotation of thedrive belt 78, swirls, mixes, and circulates the air through theinterior chamber 82, around and across the primary and secondary clutchassemblies 70 and 74 and the drive belt 78, thereby extracting heat fromand thermally cooling the primary and secondary clutch assemblies 70 and74 and the drive belt 78. The heated circulated air is then exhaustedfrom the interior chamber 82 out into the ambient environment throughthe exhaust outlet 154.

Referring now to FIGS. 4 and 8, in various embodiments, the housing 80can be formed and structured to control the air flow within interiorchamber 82. For example, in various embodiments, the housing outer cover80B can comprise a clutch dome 158 that defines a clutch alcove 162within the interior chamber 82 of the housing 80. In such instances, atleast the intake fan 98 of the primary clutch assembly 70 will bedisposed within the clutch alcove 162, and the interior face 138 of thehousing 80 comprises an interior face 138A of a top 166 of the clutchdome 158. Moreover, in such embodiments, the intake fan 98 is disposedwithin the clutch alcove 162 such that the outer face 142 of the intakefan 98 is located opposite the interior face 138A of the clutch dome top166 when the CVT 46 is assembled. Therefore, the low pressure gap 148 isdefined between the intake fan outer face 142 and the clutch dome topinterior face 138A, whereby air is drawn into the housing 80 at thecenter of the intake fan outer face 142 when the intake fan 98 isrotated. In various embodiments, the housing outer cover 80B canadditionally include an air duct 170 fluidly connected to the clutchdome alcove 162, whereby air can be directed and guided from the clutchdome alcove 162, through the air duct 170 to the area of the interiorchamber at or near the end of the housing 80 that is opposite the clutchdome 158.

Hence, ambient air drawn into the clutch dome alcove 162, via the airintake port 150, intake fan 98 and low pressure gap 148, can becirculated around and through the clutch alcove 162, then forced throughair duct 170 (via the intake fan 98) to the opposing end of the interiorchamber 82. Consequently, a portion of the air flow will be exhaustedback to the ambient environment, via the exhaust outlet 154, and aremaining portion will be circulated, swirled, and/or mixed through theinterior chamber 82, around and across the primary and secondary clutchassemblies 70 and 74 and the drive belt 78, whereafter another portionwill be will be exhausted back to the ambient environment. Thereafter,rotation of the intake fan 98 will continue to draw ambient air into theprimary clutch alcove 162, circulate the air though the interior chamber82, and exhaust air back into the ambient environment, thereby coolingthe primary and secondary clutch assemblies 70 and 74 and the drive belt78. In various embodiments, the secondary clutch assembly 74 can includea secondary clutch fan 196, as described below, that aid in thecirculation of the air through the interior chamber 82.

Referring now to FIGS. 4, 6, 7 and 9, as described above, the CVT 46comprises the primary clutch assembly 70 and the secondary clutchassembly 74, wherein the primary clutch assembly 70 includes thestationary sheave 106 and the movable sheave 110. In variousembodiments, the secondary clutch assembly 74 comprises a stationarysheave 174 and a movable sheave 178. Additionally, in variousembodiments, the clutch dome 158, described above, can be a primaryclutch dome (referred to hereafter as the primary clutch dome 158) andthe clutch alcove 162 can be a primary clutch alcove (referred tohereafter as the primary clutch alcove 162). In such embodiments, theprimary clutch assembly 70 includes the intake fan 98, as describedabove, and at least the intake fan 98 is disposed within the primaryclutch alcove 162 such that the outer face 142 of the intake fan 98 islocated opposite the interior face 138A of the primary clutch dome top166 when the CVT 46 is assembled, thereby defining the low pressure gap148.

In various instances of such embodiments, the housing outer cover 80Bcan further comprise a secondary clutch dome 182 that defines asecondary clutch alcove 186 within the interior chamber 82 of thehousing 80, wherein at least a portion the stationary sheave 174 of thesecondary clutch assembly 74 is disposed within the secondary clutchalcove 186. In various embodiments, the secondary clutch assemblystationary sheave 174 can comprise a plurality of vanes, or fins, 194integrally formed with or disposed on an outer side of the stationarysheave 174, thereby by providing a secondary clutch fan 196. In variousinstances, the vanes 194 extend radially outward from a center hub 202of the secondary clutch assembly stationary sheave 174 such that thesecondary clutch fan 196 has an annular shape and configuration whereinthe vanes 194 define an annular outer face 198 of the annular secondaryclutch fan 196. The secondary clutch fan 196 assists in cooling theprimary clutch assembly 70, secondary clutch assembly 74 and drive belt78 by swirling, mixing, and circulating the air through the interiorchamber 82, via rotation of the secondary clutch assembly 74, therebyextracting heat from and thermally cooling the primary and secondaryclutch assemblies 70 and 74 and the drive belt 78.

Moreover, in various embodiments, the secondary clutch fan 196 assistsin generating the air flow through the housing interior chamber 82, asdescribed below. Particularly, in various embodiments, the housing outercover 80B comprises an air duct 206 formed between the primary clutchdome 158 and the secondary clutch dome 182. The air duct 206 is fluidlyconnected to the primary clutch alcove 162 at a proximal end 206A andfluidly connected to the secondary clutch alcove 186 at a distal end206B. Therefore, the air duct 206 fluidly connects the primary clutchalcove 162 to the secondary clutch alcove 186. The air duct 206 guidesand controls the air flow within the interior chamber 82. Particularly,the air flow is initiated at the intake port 150 by the intake fan 98and low pressure gap 148 drawing the ambient air into the primary clutchalcove 162 at the center of the intake fan 98 (as described above), thenthe fins 146 force the air radially outward toward the distal ends ofthe fins 146 and into the primary clutch alcove 162. The location of theintake fan 98 within the primary clutch alcove 162 (as described above)and the shape/structure of the primary clutch alcove 162 direct andforce the air flowing from the fins 146 into the primary clutch alcove162, whereafter the air can be circulated around the primary clutchalcove 162 and forced into the air duct 206 toward the secondary clutchalcove 186. In various instances, the secondary clutch fan 196 isdisposed within the secondary clutch alcove 186 having the outer face198 of the secondary clutch fan 196 located opposite an interior face138B of the secondary clutch dome top 190 such that a vacuum isgenerated in the space between the secondary clutch fan outer face 198and the secondary clutch dome top interior face 138B. This vacuum willalso draw air from the primary clutch alcove 162, through the air duct206, and into the secondary clutch alcove 186.

Therefore, the air is forced into and drawn through the duct 206 via theintake fan 98 and the secondary fan 198, respectively. Consequently, aportion of the air flow will be exhausted back to the ambientenvironment, via the exhaust outlet 154, and a remaining portion will becirculated around and within the secondary clutch alcove 186, andcirculated, swirled, and/or mixed through the interior chamber 82,around and across the primary and secondary clutch assemblies 70 and 74and the drive belt 78. Thereafter, rotation of the intake fan 98 and thesecondary clutch fan 196 will continue to draw ambient air into theprimary clutch alcove 162, direct the air into the secondary clutchalcove 186, circulate the air though the interior chamber 82, andexhaust air back into the ambient environment, thereby cooling theprimary and secondary clutch assemblies 70 and 74 and the drive belt 78.

Referring now to FIGS. 6, 7 and 9, in various embodiments, the distalend 206B of the air duct 206 is fluidly connected to the secondaryclutch alcove 186 and terminates near the center hub 202 of thestationary sheave 174 of the secondary clutch assembly 74. Accordingly,air passing through the air duct 206 from the primary clutch alcove 162to the secondary clutch alcove 186 will be directed toward the centerhub 202 of the stationary sheave 174 of the secondary clutch assembly74, and more particularly toward the proximal or radially inner ends ofthe vanes 194. Therefore, the air forced and drawn through the air duct206 will be directed into the center of the annular secondary clutch fan196 such that at least a majority (e.g., 80% to 100%) of the surfacearea of at least one face of each vane 194 will be utilized to force theair radially outward from the center hub 202 to distal ends of the vanes194. Utilizing at least a majority of the surface area of at least oneface of each vane 194 will increase the velocity, volume, flow rate,circulation and thermal cooling efficiency of the air flow generated bythe intake fan 98 and secondary clutch fan 196 described above.

Referring now to FIGS. 6, 7, 8 and 9, the air duct 170/206 has a heightH^(P) at the proximal end 170A/206A and a height H^(D) at the distal end170B/206B. In various embodiments, the proximal end height H^(P) can begreater than the distal end height H^(D), thereby causing the airflowing through the air duct 170/206 to have a greater velocity and flowrate at the distal end 170B/206B than at the proximal end 170A/206A.Particularly, the air flow exiting the air duct 170/206 will have agreater velocity and flow rate than the air entering the air duct170/206, thereby increasing the velocity, volume, flow rate, circulationand thermal cooling efficiency of the air flow through the interiorchamber 82. Additionally, the air duct 170/206 has a width W^(P) at theproximal end 170A/206A and a width W^(D) at the distal end 170B/206B. Invarious embodiments, the proximal end width W^(P) is greater than thedistal end width W^(D), thereby causing the air flowing through the airduct 170/206 to have a greater velocity and flow rate at the distal end170B/206B than at the proximal end 170A/206A. Particularly, the air flowexiting the air duct 170/206 will have a greater velocity and flow ratethan the air entering the air duct 170/206, thereby increasing thevelocity, volume, flow rate, circulation and thermal cooling efficiencyof the air flow through the interior chamber 82. In various embodiments,both the proximal end height H^(P) and width W^(P) can be greater thanthe distal end height H^(D) and width W^(D).

Referring now to FIGS. 10, 11, 12 and 13, in various embodiments, thehousing 80 can comprise an internal airfoil 210 disposed between theprimary and secondary clutch assemblies 70 and 74. The airfoil 210comprises one or more walls that extend from an interior face 214 of theinner housing cover 80A to the interior face 138 of the housing outercover 80B. The airfoil 210 can be connected to, and/or integrally formwith, the housing inner cover interior face 214 and/or the housing outercover interior face 138. The airfoil 210 directs the air flow betweenthe area of the interior chamber 82 that is near and/or surrounds theprimary clutch assembly 70 and the area of the interior chamber 82 thatis near and/or surrounds the secondary clutch assembly 74 to eliminate,or substantially reduce, swirling air, and turbulence from occurring inthe area of the interior chamber 82 between the primary and secondclutch assemblies 70 and 74.

In various embodiments, the housing inner cover 80A can have a firstportion 210A (e.g., a first half) of the airfoil 210 extending outwardfrom the interior face 214 between the primary and secondary clutchassemblies 70 and 74, and the housing outer cover 80B can have a secondportion 210B (e.g., a second half) of the airfoil 210 extending outwardfrom the interior face 138 between the primary and secondary clutchassemblies 70 and 74. In various instances, the walls of first portion210A can align with and contact and the walls of the second portion 210Bwhen the housing inner and outer covers 80A and 80B are connected toform the housing 80 such that air circulating within the interiorchamber 82 cannot flow between the first and second portions 210A and210B, but rather is directed to flow around the airfoil 210 in a moredirect path between the primary and secondary clutch assemblies 70 and74. In various other instances, the walls of first portion 210A canoverlap the walls of the second portion 210B, or vice-versa, when thehousing inner and outer covers 80A and 80B are connected to form thehousing 80 such that air circulating within the interior chamber 82cannot flow between the first and second portions 210A and 210B, butrather is directed to flow around the airfoil 210 in a more direct pathbetween the primary and secondary clutch assemblies 70 and 74.

In various embodiments, the first and second portions 210A and 210B canbe structured such that one or more of the walls, or sections of one ormore of the walls, of each of the airfoil first and second portions 210Aand 210B extend from the inner faces 214 and 138 of the respectivehousing inner and outer covers 80A and 80B across the interior chamber82 and contact the opposing inner face 138 and 214, when the housinginner and outer covers 80A and 80B are connected to form the housing 80.In such embodiments, the walls, or sections of the airfoil wallsextending from the housing inner cover interior face 214 will contactand/or overlap the walls, or sections of the airfoil walls extendingfrom the housing outer cover interior face 138, or vice-versa, when thehousing inner and outer covers 80A and 80B are connected to form thehousing 80 such that air circulating within the interior chamber 82cannot flow between any section of the first and second portions 210Aand 210B, but rather is directed to flow around the airfoil 210 in amore direct path between the primary and secondary clutch assemblies 70and 74. In various other embodiments, the entire airfoil 210 can extendfrom the interior face 214 of the housing inner cover 80A such that thewalls of the airfoil 210 contact the inner face 138 of the housing outercover 80B when the housing inner and outer covers 80A and 80B areconnected to form the housing 80. Alternatively, in various embodiments,the entire airfoil 210 can extend from the interior face 138 of thehousing outer cover 80B such that the walls of the airfoil 210 contactthe inner face 214 of the housing inner cover 80A when the housing innerand outer covers 80A and 80B are connected to form the housing 80.

As described above, the airfoil 210 is sized and shaped to direct theair flow between the area of the internal chamber 82 that is near and/orsurrounds the primary clutch assembly 70 and the area of the internalchamber 82 that is near and/or surrounds the secondary clutch assembly74 to eliminate, or substantially reduce, swirling air, and turbulencefrom occurring in the area of the internal chamber 82 between theprimary and second clutch assemblies 70 and 74. Particularly, the airflow is initiated at the intake port 150 by the intake fan 98 and lowpressure gap 148 drawing the ambient air into the housing interiorchamber 82 (e.g., into the primary clutch alcove 162) at the center ofthe intake fan 98, whereafter the air can be circulated around theprimary clutch assembly 70, (e.g., around the clutch alcove 162) andforced toward the secondary clutch assembly 74 at the opposing end ofthe interior chamber 82 (e.g., forced into the air duct 170 toward thesecondary clutch assembly 74 at the opposing end of the interior chamber82) or (e.g., forced into the air duct 206 and into the secondary clutchalcove 186). The air will then circulate around the secondary clutchassembly 74 (e.g., circulate within the secondary clutch alcove 186 andaround the secondary clutch assembly 74). Thereafter, a portion of theair flow will be exhausted back to the ambient environment, via theexhaust outlet 154, and a remaining portion will be directed back towardthe primary clutch assembly 74 (e.g., directed back toward the primaryclutch alcove 162 and primary clutch assembly 70) in a substantiallydirect path via the airfoil 210. Subsequently, the air returning in thesubstantially direct path from secondary clutch area of the interiorchamber 82 will mix with air being drawn into the housing interiorchamber (e.g., being drawn into the primary clutch alcove 162), via theintake port 150. The combined fresh and recirculated air will then becirculated around the primary clutch assembly 70, (e.g., around theclutch alcove 162) and forced toward the secondary clutch assembly 74 atthe opposing end of the interior chamber 88, as described above,whereafter a portion thereof will be exhausted and a portionrecirculated, as described above, thereby extracting heat from andthermally cooling the primary and secondary clutch assemblies 70 and 74and the drive belt 78.

Hence the airfoil 210 will direct the air within the interior chamber 82to flow in a substantially direct path from the area surrounding theprimary clutch assembly 70, along the area in which the drive belt isdisposed, to the area surrounding secondary clutch assembly 74, and fromthe area surrounding the secondary clutch assembly 74, along the area inwhich the drive belt is disposed, back to the area surrounding theprimary clutch assembly 74. Moreover, the airfoil 210 will prevent theair flow from swirling, mixing and/or causing turbulence within themiddle or central area of the interior chamber 82 between the primaryand secondary clutch assemblies 70 and 74, thereby increasing thevelocity, volume, flow rate, circulation and thermal cooling efficiencyof the air flow. The airfoil 210 can have generally any desired shapeand size suitable for directing the airflow within the interior chamber82 as described above. For example, as illustrated by way of example inFIGS. 10, 11, 12 and 13, in various embodiments the airfoil 210 can havean open or closed elongated C-shape, wherein the airfoil 210 has lengthL that substantial spans the area within the interior chamber 82 betweenthe primary and secondary clutch assemblies 70 and 74. For example, theairfoil 210 can have a length L that positions a first end of theairfoil 210 nearly in contact with the stationary and movable sheaves106 and 110 of the primary clutch assembly 70 (e.g., the first end isapproximately 0.10 to 0.25 inches away from stationary and movablesheaves 106 and 110 of the primary clutch assembly 70), and positions anopposing second end of the airfoil 210 nearly in contact with thestationary and movable sheaves 174 and 178 of the secondary clutchassembly 74 (e.g., the second end is approximately 0.10 to 0.25 inchesaway from stationary and movable sheaves 174 and 178 of the secondclutch assembly 74).

The description herein is merely exemplary in nature and, thus,variations that do not depart from the gist of that which is describedare intended to be within the scope of the teachings. Moreover, althoughthe foregoing descriptions and the associated drawings describe exampleembodiments in the context of certain example combinations of elementsand/or functions, it should be appreciated that different combinationsof elements and/or functions can be provided by alternative embodimentswithout departing from the scope of the disclosure. Such variations andalternative combinations of elements and/or functions are not to beregarded as a departure from the spirit and scope of the teachings.

What is claimed is:
 1. A continuously variable transmission clutchassembly, said assembly comprising: a clutch post that is operablyconnectable to an output shaft of a vehicle prime mover; a movablesheave movably mounted on the clutch post; a stationary sheave fixedlymounted on the clutch post opposite a front face of the movable sheave;and an intake fan that is a separate and independent component from themovable sheave and is fixedly mounted to the clutch post separate andindependent from the movable sheave opposite and spaced apart from arear face of the movable sheave such that the intake fan is spaced apartfrom the movable sheave.
 2. The assembly of claim 1, wherein the intakefan comprises a plurality of fins that define an outer face of theintake fan, and wherein the intake fan is mounted to the clutch postsuch that when the assembly is enclosed within a transmission housingthe outer face of the intake fan will be located opposite an interiorface of the transmission housing such that a low pressure gap will bedefined between the outer face of the intake fan and the interior faceof the transmission, whereby air will be drawn into the transmissionhousing at least near a center of the intake fan outer face when theintake fan is rotated by the clutch post.
 3. A continuously variabletransmission, said transmission comprising: a housing comprising aninner cover and an outer cover connected to the inner cover to providethe housing having an interior chamber defined therein; and a clutchassembly disposed within the housing interior chamber, the clutchassembly comprising: a clutch post that is operably connectable to anoutput shaft of a vehicle prime mover; a movable sheave movably mountedon the clutch post; a stationary sheave fixedly mounted on the clutchpost opposite a front face of the movable sheave; and an intake fan thatis a separate and independent component from the movable sheave and isfixedly mounted to the clutch post separate and independent from themovable sheave opposite and spaced apart from a rear face of the movablesheave such that the intake fan is spaced apart from the movable sheave.4. The transmission of claim 3, wherein the intake fan comprises aplurality of fins that define an outer face of the intake fan, andwherein the intake fan is mounted to the clutch post such that the outerface of the intake fan will be located opposite an interior face of thehousing outer cover such that a low pressure gap will be defined betweenthe outer face of the intake fan and the interior face of the housingouter cover, whereby air is drawn into the transmission housing at leastnear a center of the intake fan outer face when the intake fan isrotated by the clutch post.
 5. The transmission of claim 4, wherein thehousing outer cover comprises a clutch dome that defines a clutch alcovewithin the interior chamber of the housing, wherein the interior face ofthe housing comprises an interior face of a top of the clutch dome, andwherein the intake fan is disposed within the clutch alcove such thatthe outer face of the intake fan is located opposite the interior faceof the clutch dome top such that the low pressure gap is definedtherebetween, whereby air is drawn into the transmission housing atleast near a center of the intake fan outer face when the intake fan isrotated by the clutch post.
 6. The transmission of claim 5, wherein theclutch assembly is a primary clutch assembly and the transmissionfurther comprises a secondary clutch assembly having a movable sheaveand a stationary sheave, and wherein the clutch dome is a primary clutchdome defining a primary clutch alcove and the housing outer coverfurther comprises: a secondary clutch dome that defines a secondaryclutch alcove within the interior chamber of the housing, wherein atleast a portion of the stationary sheave of the secondary clutchassembly is disposed within the secondary clutch alcove; and an air ductformed between the primary clutch dome and the secondary clutch domefluidly connecting the primary clutch dome to the secondary clutch dome,the air duct being fluidly connected to the primary clutch dome at aproximal end and fluidly connected to the secondary clutch dome at adistal end.
 7. The transmission of claim 6, wherein at least one of aheight and a width of the air duct is greater at the proximal than atthe distal end.
 8. The transmission of claim 6, wherein the distal endof the air duct is fluidly connected to the secondary clutch dome suchthat air passing through the air duct from the primary clutch dome tothe secondary clutch dome will be directed toward a center hub of thestationary sheave of the secondary clutch assembly.
 9. The transmissionof claim 3, wherein the housing outer cover comprises an air intake portdisposed in the outer cover opposite a center of the intake fan.
 10. Thetransmission of claim 3, wherein the clutch assembly is a primary clutchassembly and the transmission further comprises a secondary clutchassembly having a movable sheave and a stationary sheave, wherein atleast one of the housing inner cover and the housing outer covercomprises at least a portion of an airfoil disposed on at least one ofan interior face of the housing inner cover and an interior face of thehousing outer cover, the airfoil sized and shaped to extend into thehousing interior chamber between the first and secondary clutchassemblies from the housing inner cover interior face to the outer coverinterior face.
 11. A continuously variable transmission housing, saidhousing comprising: an inner cover; and an outer cover connected to theinner cover to provide the housing having an interior chamber definedtherein, the interior chamber structured to enclose a continuouslyvariable transmission primary clutch assembly, a continuously variabletransmission secondary clutch assembly, and a continuously variabletransmission drive belt, wherein at least one of the inner cover and theouter cover comprises at least a portion of an airfoil disposed on atleast one of an interior face of the inner cover and an interior face ofthe outer cover, the airfoil sized and shaped to span the housinginterior chamber from the inner cover interior face to the outer coverinterior face between the primary and secondary clutch assemblies whenthe primary clutch, secondary clutch and drive belt are enclosed withinthe housing.
 12. The housing of claim 11, wherein the housing outercover comprises an air intake port disposed in the outer cover such thatthe air intake port will be opposite a center of the primary clutchassembly when the primary clutch, secondary clutch and drive belt areenclosed within the housing.
 13. The housing of claim 11, wherein thehousing outer cover comprises: a primary clutch dome that defines aprimary clutch alcove within the interior chamber of the housing, theprimary clutch alcove structured to receive at least a portion of theprimary clutch assembly when the primary clutch is enclosed within thehousing; a secondary clutch dome that defines a secondary clutch alcovewithin the interior chamber of the housing, the secondary clutch alcovestructured to receive at least a portion of the secondary clutchassembly when the secondary clutch is enclosed within the housing; andan air duct formed between the primary clutch dome and the secondaryclutch dome fluidly connecting the primary clutch dome to the secondaryclutch dome, the air duct being fluidly connected to the primary clutchdome at a proximal end and fluidly connected to the secondary clutchdome at a distal end.
 14. The housing of claim 13, wherein at least oneof a height and a width of the air duct is greater at the proximal thanat the distal end.
 15. The housing of claim 13, wherein the distal endof the air duct is fluidly connected to the secondary clutch dome suchthat air passing through the air duct from the primary clutch dome tothe secondary clutch dome will be directed toward a center hub of thestationary clutch sheave when the secondary clutch is enclosed withinthe housing.